1. Field of the Invention
This invention pertains to devices for loading pipe onto a machine having a pipe receiving location. More particularly, this invention pertains to an automatic pipe loading apparatus for an underground boring machine.
2. Description of the Prior Art
In the prior art, machines exist requiring periodic placement of pipe on the machine. An example of such is an underground directional boring machine which forces a length of pipe through the ground in order to form a bore. After the bore is formed., a cable or the like may be passed through the bore. Such underground boring machines eliminate the need to dig a long trench into which a cable is then laid.
In underground boring machines, a fixed length of pipe is placed on a machine and then forced into the ground. After the full length of the pipe has been forced into the ground, a subsequent length of pipe is placed on the machine and coupled to the first length. The combined length is then further forced into the ground. A third length of pipe is then placed on the machine and coupled to the second length. In order to form a complete bore, numerous lengths of pipe must be placed on the machine.
Pipes used in directional boring machines come in a variety of lengths and weights. For example, in the directional boring industry, 10 foot long pipes weighing about 70 pounds each are frequently used. Fifteen foot pipes weighing from 100-150 pounds each are also used.
In the prior art, a load of pipe is delivered to the work site and a worker must pick up each individual pipe and manually place it on the boring machine. It will be appreciated that where substantial lengths of pipe are required, an individual worker must lift and place a substantial number of heavy pipes. Indeed, for 15 foot pipes, two workers may be necessary to load and place a single pipe. It is therefore desirable to automate loading of pipe and eliminate the need for a worker to lift and place substantial numbers of heavy pipes.
Automatic pipe loading machines exist in the prior art. One such example is shown in commonly assigned and copending U.S. patent application Ser. No. 08/438,696. However, the automatic pipe loading machines in the prior art do not cycle the pipes used in the machine. Because some pipes are used more frequently than others, the pipes wear unequally. Therefore, it is desirable to have an automatic pipe loading machine that will cycle the usage of the pipes to insure that the pipes wear equally.